DFT · Topic
Memory BIST — March Algorithms & Memory Test
Built-in self test for memories — why scan cannot test arrays, march algorithms, BIST controllers and repair.
Scan and ATPG cannot test a memory array, because the array is not made of scan flops and its fault behaviour is not captured by a stuck-at model. Memories fail in their own ways — coupling between cells, address decoder faults, retention — so they get their own test engine on the die. March algorithms are the standard answer: a defined sequence of writes and reads that provably detects a stated class of memory faults in linear time.